AVP and infection: From a comparison of the different outcomes of Adh-knockout (5bΔAdh) and wild-type (5b WT) strains in the infection of piglet porcine primary alveolar macrophages, mice and piglets, we found that Adh not only mediates bacterial adhesion to host cells but also induces PAMs to undergo apoptosis and release IL-8, which results in the recruitment of excessive inflammatory cells to the lungs.